Reducing Greenhouse Gas Emissions from Municipal Solid Waste Incineration by Carbon Capture and Enhanced Recycling

Abstract

The Dutch waste incineration industry is one of the most efficient in the world, extracting 36% of the energy in the waste as useful heat or electricity on average, while reducing the volume of the solid municipal waste by around 90% (Rijkswaterstaat, 2020). Consequentially, the industry is also one of the Netherlands’ largest emitters of greenhouse gases. In 2018, the industry emitted 7.5 Mt of CO2- equivalent emissions, of which 3.0 Mt was non-biogenic in origin. In order to achieve the climate ambitions of the Dutch government of 60% GHG emission reduction and net-zero emissions in 2050, the waste incineration industry is under pressure to reduce its emissions (Rijksoverheid, 2018).

This research, conducted in the context of the MIDDEN project, attempts to compare different technologies, configurations and pathways for the reduction of GHG emissions related to the currently incinerated waste stream in the Netherlands. The two main categories that were investigated were carbon capture technologies and enhanced recycling technologies. Emission reduction options are compared on the basis of their technology readiness level, potential feedstock, total CO2 emission reduction potential and estimated CO2 avoidance cost. The net emission reduction potential is estimated by an ex-ante comparative life cycle assessment. Validation of the results is done via a Monte Carlo analysis of uncertainty.

Carbon capture for waste incinerators is already an established technology, which is currently applied at two major waste incinerators in the Netherlands. This report identified three configurations for carbon capture technologies and assessed their potential for emission reduction and associated cost. CO2 avoidance cost ranged from €159-224 per tonne CO2, depending on the configuration chosen. Furthermore, policy issues that hinder implementation of carbon capture are addressed in the discussion.

Enhanced recycling aims at decreasing the total volume of incinerated waste, while reducing net GHG emissions. Enhanced recycling technologies identified by this research with the potential of reducing GHG emissions are waste plastic pyrolysis, EPS solvolysis, PET depolymerisation and gasification of municipal solid waste. Findings include limited total GHG emission reduction potential for enhanced recycling (154 kt CO2 annually) compared to carbon capture technologies (5,130 kt annually). A configuration combining recycling (gasification) and CCS was found to result in 1,043 kt CO2 reduction annually. In part, this is due to the limited availability of the feedstock for these processes. Another factor is the emissions from the alternative processes themselves. CO2 avoidance cost results for enhanced recycling technologies were inconclusive, as uncertainty was found to be too large.

Significant short-term CO2 emission reduction is most likely achieved through large-scale implementation of carbon capture technologies in combination with waste incineration and/or gasification. Carbon capture and storage proves to be the most potent short-term solution to waste incineration GHG emissions. In the long-term, GHG emission reduction must be achieved by full separation of the plastic waste from the residual fraction and subsequent recycling of this plastic material. The methods and practices to achieve this, however, are not available at this time.